England manager Martin Johnson has defended his multi-national World Cup training squad in the face of criticism from one of the major casualties.

Gloucester flanker Luke Narraway captained England against the Barbarians at Twickenham less than a month ago but could not break into a 45-man group announced today that contained 13 overseas-born players. Narraway missed out to Leicester's New Zealand-born No.8 Thomas Waldrom, who only discovered he was eligible for England midway through the Premiership season.

Narraway, who was set to spearhead the England Saxons' recent Churchill Cup campaign before being ruled out with a back injury, took to Twitter to vent his frustrations at being overlooked for Waldrom. Narraway posted: "Good luck to Thomas the tank and his English nan. #notbittermuch."

Johnson named a cosmopolitan England training squad, consisting of players born in eight different countries, with four New Zealand-born players (Waldrom, Dylan Hartley, Shontayne Hape and Riki Flutey) featuring alongside three South African's (Mouritz Botha, Hendre Fourie and Matt Stevens).

Johnson defended his decision and insisted the only message it sent to young English players was the continual need to strive for improvement. Uncapped Gloucester wing Charlie Sharples, Harlequins captain Chris Robshaw and Saracens scrum-half Richard Wigglesworth have all been rewarded for impressive seasons.

"There are a lot of good players coming through the academies," said Johnson. "If you want to play for England, play well in the Premiership and be good enough to come in here because it is a competitive place. Those two guys [Waldrom and Botha] come in for the first time and, it's the same for Charlie Sharples, you have to establish yourself in this group.

"The other members of the team need to understand you are there to work hard, fit in and contribute. I have seen guys born abroad who have done that and guys born in England do that - and the same who haven't done it. They are in the same place as everyone else. You show your commitment to the cause every day, in how you train, how you play, who you are. They are in with a shot and deserve their chance."

England have a long tradition of employing foreign-born talent from the likes of Russian prince Alexander Obolensky to a more recent servant like South African Mike Catt but concerns have been expressed at the number of overseas-born players now in the squad.

As ever, it is not a black and white situation. Alex Corbisiero, Joe Simpson and Delon Armitage all came to England as youngsters while Hartley was 16 when he moved from New Zealand. They all developed through the English club academy system. Others are more open to claims of opportunism.

Hape was a Kiwi rugby league international, Flutey played for the Maori against the 2005 Lions. Waldrom is the latest New Zealand import. The 28-year-old from Lower Hutt discovered his English heritage midway through his debut season for Leicester, which he finished on the bench behind Jordan Crane. Although Narraway and Crane both captained England's second string in the last month, and Phil Dowson excelled for Northampton again this season, it was Waldrom who got the nod.

Botha and Fourie both came to England after deciding their rugby careers were going nowhere in South Africa and have ended up on the international radar. Tuilagi, the hard-hitting Leicester centre and Premiership young player of the year, is different again. The 20-year-old was nearly deported last year after it emerged he had originally entered the country on a six-month holiday visa seven years ago.

Tuilagi, who has four brothers who played for Samoa, was granted indefinite leave to stay and declared his international allegiance to England. Johnson would have used the Churchill Cup to have a closer look at Tuilagi but he was banned - he still is, technically - for punching Chris Ashton in the Premiership semi-final.

Armitage served two periods of suspension last season, one for abusing a drug tester and the other for punching Northampton's Steven Myler. Johnson is confident both have the temperament to cope with a World Cup but he has issued a strong warning about the need to behave.

"We can't have guys getting suspended down there for events on or off the field," said Johnson. "We are in New Zealand. We all know what that is like, it is a goldfish bowl. And you are at the World Cup so you are in a goldfish bowl within a goldfish bowl.
"We need guys who are available to play. We don't need silly suspensions because it puts us all under pressure."

Johnson's selection also included a return to the senior squad for Stevens, who won the last of his 32 caps in November 2008, a month before testing positive for cocaine.
Stevens returned to action in January and he has not been on a losing side since, helping Saracens win the Aviva Premiership title and the England Saxons to Churchill Cup success.

"Two years is a long time out of top level sport and he has done well to get himself back into a position to come back here now," said Johnson. "He knows the hard work has only just started."

Johnson will name his final 30-man squad for the tournament in New Zealand on August 22, before the final warm-up match against Ireland.